Communication systems have become more sophisticated and advanced over the past several decades. For example, many traditional communication devices utilized only one or two microphones to sense sound from a near-end user. Although these more basic systems produced echo caused by the pickup of sound from a far-end user played through a near-end speaker, this echo could be efficiently controlled through the use of a dedicated echo canceller assigned to each microphone.
As communication systems have advanced, the number of microphones associated with these systems has increased. For example, microphone arrays, which are composed of multiple individual microphones, may be used for detecting sound in the vicinity surrounding a modern communication device. Similar to traditional systems, signals produced by each microphone in these modern devices may require processing to remove echo associated with audio playback of far-end sounds. However, due to the number of microphones in these systems, dedicated echo cancellation for each microphone may be unwieldy and/or impractical.
Further, many modern systems may require stereo echo cancellers to handle the imaging of correlated sounds through multiple speakers. Such echo cancellers can be even more complex than their monophonic counterparts given the need to handle multiple reference signals. This further constrains the number of echo cancellers that can be run at one time. In addition, stereo echo cancellation may lead to non-unique solutions which depend on a far-end sound source's position. Although de-correlation techniques may be used to assist in stereo echo cancellation, these de-correlation techniques may introduce artifacts into the signals. Further, even with the utilization of de-correlation techniques, and beyond handling multiple reference signals, more complex adaptation methods such as recursive least-squares (RLS) processes may still be needed to obtain faster convergence times by associated echo cancellers.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.